Re: [PATCH 5/9] drm/xe/rtp: Save OA nonpriv registers to register save/restore lists

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Wed, 27 May 2026 15:00:38 -0700, Umesh Nerlige Ramappa wrote:
>
> On Mon, May 18, 2026 at 04:47:12PM -0700, Ashutosh Dixit wrote:
> > Now we can save OA whitelisting nonpriv registers to register save/restore
> > lists. OA nonpriv registers are saved to both hwe->oa_sr as well as
> > hwe->reg_sr, for reasons explained in coments.
> >
> > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> > ---
> > drivers/gpu/drm/xe/xe_reg_whitelist.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_reg_whitelist.c b/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > index 6d42c00c1d75b..18053582a6afa 100644
> > --- a/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > +++ b/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > @@ -216,6 +216,17 @@ void xe_reg_whitelist_process_engine(struct xe_hw_engine *hwe)
> >
> >	xe_rtp_process_to_sr(&ctx, oa_whitelist, ARRAY_SIZE(oa_whitelist),
> >			     &hwe->oa_whitelist, false);
> > +	/*
> > +	 * Save oa nonpriv registers to hwe->oa_sr, from which oa registers are whitelisted
> > +	 * or de-whitelisted, by toggling the 'deny' bit on oa stream open/close
> > +	 */
> > +	whitelist_apply_to_hwe(hwe, &hwe->oa_whitelist, &hwe->oa_sr, nonpriv_slots);
> > +
> > +	/*
> > +	 * Also save oa nonpriv registers to hwe->reg_sr, to ensure oa registers are not
> > +	 * whitelisted by default after probe/reset/restart
> > +	 */
> > +	whitelist_apply_to_hwe(hwe, &hwe->oa_whitelist, &hwe->reg_sr, nonpriv_slots);
>
> I would prefer that we fail if the registers overshoot the max slots for
> whitelisiting, but not sure why the overshoot is just a gt error log.

Yes, this is pre-existing, but I believe it is to not fail the probe if we
overshoot. The last time I ran into a situation like this, I was told that
it is better to continue with reduced functionality, rather than no
functionality at all.

Also, xe_gt_err() will signal a failure in our CI, so the error will not be
missed.

>
> Also, max NONPRIV slots should be bumped up to 20 for Xe.

There is this:

https://patchwork.freedesktop.org/patch/717191/?series=159772&rev=5

Though I believe the patch is incorrect, I will respond separately to
this. A couple of other patches from the above series will also be nice to
have.

As I mentioned, I want to focus this series only on removing unconditional
whitelisting for OA registers. Once this is merged, I am planning to have a
follow-up series with changes such as this. E.g. the 'head' value in
WHITELIST_OA_MERT_MMIO_TRG is incorrect (not a multiple of 16, as is
required for RANGE_4), so that needs to be fixed too.

Thanks.
--
Ashutosh


>
> Umesh
> > }
> >
> > /**
> > --
> > 2.54.0
> >